1. Technical Field
The present disclosure relates generally to a wireless communication terminal, and more particularly, to an antenna device of a wireless terminal for transmitting/receiving a wireless signal.
2. Description of the Related Art
A wireless communication terminal (“wireless terminal”) is generally any electronic device capable of wirelessly receiving and/or transmitting an information signal or communication signal. Wireless terminals include mobile terminals such as cell phones and smart phones, traditionally used as a medium for simple communication, such as voice communication or short message transmission. Recently, owing to the development of communication technologies, a user may quickly obtain a large variety of information through a wireless terminal In addition, it becomes possible to receive satellite broadcasting or terrestrial broadcasting. Furthermore, for example, a credit card function is incorporated in a wireless terminal The development of electronic communication technologies has made it possible to incorporate, for example, a multimedia function, an entertainment function, a digital organizer function, a banking function, and a security function in a single mobile terminal based on a communication function.
Since a wireless terminal is used while it is hand carried, lightweight and miniaturized designs are preferable. A circuit of, e.g., a processing device that executes various functions may be miniaturized by increasing the integration degree of an integrated circuit chip. However, some elements have a limit in miniaturization. For example, a battery pack is capable of supplying power for a predetermined length of time which is in proportion to the volume and capacitance of the battery pack. In addition, at today's cell phone frequency bands, it is practically impossible to physically incorporate antenna devices in a single module or chip. Therefore, in relation to the elements such as the battery pack and the antenna pack of which the sizes are difficult to physically reduce, efforts are continually made to reduce the size of a terminal by optimizing the arrangement of the elements inside the terminal.
Meanwhile, as described above, as the functions of wireless terminals have diversified, the number of antenna devices within a terminal has also increased. Early terminals were only equipped with an antenna required for a mobile communication function. However, three or four types of antennas are now commonly provided within a single terminal, including an antenna for short-range wireless communication, such as wireless LAN and Blue-tooth, and a broadcasting receiving antenna.
Because the mobile communication or short-range wireless communication usually uses frequencies in a band of several GHz, an antenna device having a relatively short electric length is used. Therefore, an antenna for these applications is easy to physically miniaturize and thus, is suitable to be accommodated in a terminal. In contrast, an antenna device for a frequency band of tens to hundreds of MHz (VHF) or a band of several hundred MHz (UHF) like terrestrial broadcasting has a considerable electric and physical length and thus, has a limit to be accommodated inside a small wireless terminal. Therefore, a broadcasting antenna provided in a wireless terminal is generally provided in a removable structure based on an earphone cable or whip antenna structure, or is accommodated in the terminal in a multi-stage whip antenna structure.
A removable antenna is mounted on a terminal during use of the terminal. Therefore, the removable antenna is advantageous in miniaturizing and lightening the terminal However, a disadvantage is the need to separately carry the broadcasting antenna when it is removed. Accommodating a whip antenna of a multi-stage structure in a terminal is advantageous in that the terminal is easy to carry although it is somewhat unsuitable for miniaturizing and lightening the terminal However, an antenna of a frequency band of tens to hundreds of MHz usually has a length of at least about 20 cm and up to about 40 cm when it is fully drawn out from the terminal and thus, the antenna is disadvantageously inconvenient to use while the user is moving during practical use.